Late clinical and hemodynamic observations are described in 6 patients who had either tricuspid valve anuloplasty (TVA) (2 patients) or tricuspid value replacement (TVR) (4 patients) 5 to 132 months earlier for Ebstein's anomaly of the tricuspid valve unassociated with right ventricular outflow obstruction. Of the 6 patients, 5 postoperatively had improved by 1 New York Heart Association functional class and 1, by 2 functional classes. The cardiothoracic ratio decreased 5-12 months after either TVR or TVA in all 6 lpatients (from a mean of 0.72 to 0.62). Repeat cardia catheterization 5-12 months after TVA or TVR disclosed that the right atrial mean pressure had increased from a median of 4.0 to 10.5 mm Hg (p=0.05); that the right ventricular peak systolic pressure had increased from 19.0 to 31.5 mm Hg (p=0.02); that the right ventricular end-diastolic pressure had increased from 5.0 to 9.0 mm Hg (p=0.05); that the systemic arterial peak systolic pressure had increased from 115 to 123 mm Hg (p=0.03), and that the cardiac index had increased (in all 4 patients in whom both pre-and postoperative values were available) from 1.7 to 2.9 L/min/m2 (p=9,06). Thus, the tricuspid valve operations in our 6 patients with Ebstein's anomaly were associated with a decrease in symptoms of cardiac dysfunction, a decrease in cardiac size, and increase in cardiac index and an increase in right ventricular and right atrial pressures. The elevation of the right atrial pressures postoperatively may have resulted from increased right ventricular filling pressures, persistent tricuspid regurgitation, or bioprosthetic stenosis.